Plastic bags with metal foil laminated lips



Nov. 21, 1967 J. H. PICKIN 3,353,662

PLASTIC BAGS WITH METAL FOIL LAMINATED LIPS Filed April l5, 1964 nf' lll2| INVENTOR JOHN HARLAN P/CK//V ATTORNEYS United States Patent G3,353,662 PLASTIC BAGS WITH METAL Fll. LAMINATED LIPS John HarlanPickin, Madison, NJ., assignor to Colgate- Palmolive Company, New York,N.Y., a corporation of Delaware Filed Apr. 15, 1964, Ser. No. 359,897 2Claims. (Cl. 20G-59) This invention relates to plastic bags andparticularly to such bags wherein metal foil strips are surface bondedalong the edge areas at the open end of the bag.

The invention in its preferred embodiment will be described as appliedto thin walled transparent plastic bags such as are used for packagingand storing foods, garbage, loose articles or the like.

These bags are currently made of limp low density grade polyethylenefilm sheeting of only between one to three thousands of an inch inthickness. These bags when ready for use are closed except for one endthat is open to receive the contents, After the contents are insertedthe bag is closed by folding back or rolling over the edge area at theopen end. Considerable difficulty has been encountered in closing thesethin walled bags because of the tendency of the folded over plasticmaterial to remember its original state which causes it to uncurl andunfold to reopen the bag.

These bags may for example be of the type disclosed in United StatesLetters Patent No. 2,759,648 to Piazze issued Aug. 21, 1956. Theyusually are integral sections of a long tubular web of the bag materialthat is attened and wound on a dispenser roll with sealed transverseareas defining the bag bottoms and adjacent transverse score linesenabling an individual bag sized section to be torn olf when the roll ismounted in a suitable dispenser casing.

It has been proposed to provide these individual -bag sections withadhesive coatings for sticking together the open bag end lips after thecontents are inserted, but this has proved to be impractical indispensing in that a parting sheet or the like must be provided toprevent premature bonding of contacting surfaces of the roll in thedispenser. Other modes of bag closure involve separately attachedelements or expensive structure, and none have proved suitable indispensing assemblies prior to the invention.

The invention provides the bag side area adjacent the bag opening with astrip of suitable crimpable material, which is preferably a thin metalfoil, full surface bonded in laminated permanent attachment to theplastic wall of the bag.

It is therefore the major object of the invention to provide a novelvery thin walled plastic bag structure wherein crimpable materialcapable of retaining a given fold or shape is full surface bonded uponthe Ibag side along the edge of the bag opening.

Another object of the invention is to provide a novel bag structurehaving walls of thin plastic sheet material such as low densitypolyethylene of as little as one to three thousandths of an inch inthickness having one or more bands or strips of crimpable mate-rial suchas very thin aluminum or like metal foil surface bonded to the plasticbag along the area or areas at the periphery of the opening.

Further objects of the invention will appear as the description proceedsin connection with the appended claims and the annexed drawings wherein:

FIGURE 1 is a side elevation of a thin walled plastic bag laminated withmetal foil strips along the edges of the open end according to apreferred embodiment of the invention;

FIGURE 2 is an end elevation looking into the open end of the bag ofFIGURE 1;

FIGURE 3 is a greatly enlarged fragmentary view in 3,353,662 PatentedNov. 21, 1967 ICC section on line 3 3 of FIGURE 1 showing the laminatedplastic and metal foil at the open end of the bag;

FIGURE 4 is a side elevation like FIGURE 1 but with the laminated edgearea folded over to close the bag;

FIGURE 5 is a greatly enlarged fragmentary view in section on line 5 5of FIGURE 4 showing the folded over structure;

FIGURE 6 is a side elevation showing the bag of FIG- URE 4 with thefolded edge area of FIGURE 4 crimped transversely of the bag;

FIGURE 7 is an enlarged end view diagrammatically showing the crimpedclosed open end of the bag viewed On line 7 7 of FIGURE 6;

FIGURE 8 is a diagrammatic view showing the invention wherein successivebag sections are integrally connected for dispensing.

The individual plastic bag 11 which is so limp that it lies essentiallyflat prior to use has all of its ends closed except the open endindicated at 12. Bag 11 is preferably made of light weight thintransparent thermoplastic polyethylene about 0.001 inch thick, Aconvenient size for such bags in flat condition is about about twelveinches in length and twelve inches wide. In the invention, two similarstrips or bands 13 and 14 of aluminum foil each about two inches wideare adhesively full surface bonded across the bag edge areas. One sideedge of each foil strip is preferably flush, with the open edge 15 ofthe bag. Each foil strip is twelve inches long, and in one successfulembodiment the foil is aluminum foil about 0.0007 inch thick. If desireda single foil strip 24 inches long may be bonded around the open end ofthe bag.

After the contents are placed in the bag, the bag is closed by doublingover the laminated edge area as shown in FIGURES 4 and 5. Then, seeFIGURES 6 and 7, if desired for more secure closure the folded over edgearea of FIGURE 4 is longitudinally crimped transversely of the bag toprovide a closely crimped end region indicated at 16. For example withthis bag full of water and the edge area folded upon itself andlongitudinally crimped as described, this provides a water tight closureeven when the bag is upended.

FIGURE 8 shows the invention aas applied to a tubular length of the bagmaterial wound flat upon a roll 20. The individual bag sections 21 areseparated -by transverse sealed areas 22 and transverse score lines 23as in said Piazze patent. However, bonded upon the tubular bag materialon the opposite side of the score line 23 from the sealed area 22 in theinvention are transverse laminated crimpable strips 24 Whose side edge25 may coincide with the score lines to facilitate tearing off the bagsection. When a bag section 21 is torn off the strip `of FIGURE 8 itwill appear as shown in FIGURE l.

While the preferred embodiment employs a relatively wide band of metalfoil laminated upon the plastic around the open end of the bag, it iswithin the scope of the invention to effect the closure by bonding onlya single twelve inch long metal foil strip of suitable width along oneside edge area, or by replacing one or more strips 13 and 14 by stifffoldable paper of suitable characteristics, or even laminates of paperand foil. In all embodiments a suitable wide strip of crimpable sheetmaterial is full surface bonded along the edge area at the mouth of theopen bag. This strip preferably has a side edge ush with the open endedge of the lbag as shown in FIGURE 1, and its length is preferably atleast equal to one-half the periphery of the open end of the bagalthough it may be made up of aligned sections.

The term crimpable sheet material is intended to include metal foil,stiff paper and metal foil laminates, any of which possess the necessarycharacteristic of being capable of a so-called shape retaining deadfold. In other words the material will retain a given fold or crimp, and

in the as-sembly such prevents unfolding and uncurling of the thin imsyplastic at the open end of the bag. If desired the crimpable sheetmaterial may be 4bonded to the inner edge areas of the bag openingrather than the outer areas as disclosed in the preferred embodiment.

Any suitable exible adhesive which will bond the plastic and aluminumfoil in permanent -full surface lam.- ination and will not capture orseparate when folded can be employed. A preferred adhesive forpolyethylene bags of this type is one composed of suitable proportionsof polyvinyl chloride resin and thermoplastic chlorinated diphenyls in aliquid vehicle of toluene and containing a suitable antioxidant. Apreferred formula is:

Material: Parts by weight Polyvinyl chloride (Elvax 150 Du Pont) 30.Ohlorinated diphenyl oil (Aroclor 5460 Monsanto) 40. Chlorinateddiphenyl resin (Aroclor 1254 Monsanto) 30. Antioxidant (Ethyl Corp.Antioxidant 720) 0,0025 Toluene 600.

This adhesive is applied as by spraying onto the metal strip surface andallowed to air dry for about five minutes until it is adequately tacky.Then the strip is pressed in place onto the plastic bag area. Thetoluene it is belieVed combines to dissolve some of the plastic at thebag surface before it evaporates, leaving a good full surface bondbetween the strip and bag.

It is important to use a suitably flexible adhesive at the interfacesmarked 17 in FIGURES 3 and 5 to permit such small relative movements ofthe foil and plastic sheet surfaces as are involved in the folding andcrimping actions without causing separation of the surfaces or causingsurface Wrinkles in the foil or plastic between the fold lines.

The invention may be embodied in other specic forms Without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoing descrip*-tion, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. A dispensing system for plastic bags comprising a long tubular bodyof very thin highly Vflexible thermoplastic sheet material which isnormally flat wound into a roll, said body being heat sealed thereacross at longitudinally spaced transverse areas to divide it intoindividual bag sections and being provided with transverse weakenedregions adjacent and parallel to said heat sealed areas, and transversebands of crimpable material surface Y bonded to said body at theoppositey sides of said weakened regions from said lheat sealed areas sothat each of said weakened regions extends across said body anked onopposite sides by one of said bands and one of said heat sealed areas,whereby individual bag sections having said bands at their open ends maybe detached lfrom said body by tearing at said weakened sections.

2. The dispenser system defined in claim 1 wherein an edge of each ofsaid bands lies along a weakened region.

References Cited LOUIS l. MAINCVENE, Primary Examiner.

1. A DISPENSING SYSTEM FOR PLASTIC BAGS COMPRISING A LONG TUBULAR BODYOF VERY THIN HIGHLY FLEXIBLE THERMOPLASTIC SHEET MATERIAL WHICH ISNORMALLY FLAT WOUND INTO A ROLL, SAID BODY BEING HEATED SEALED THEREACROSS AT LONGITUDINALLY SPACED TRANSVERSE AREAS TO DIVIDE IT INTOINDIVIDUAL BAG SECTIONS AND BEING PROVIDED WITH TRANSVERSE WEAKENEDREGIONS ADJACENT AND PARALLEL TO SAID HEAT SEALED AREAS, AND TRANSVERSEBANDS OF CRIMPABLE MATERIAL SURFACE BONDED TO SAID BODY AT THE OPPOSITESIDES OF SAID WEAKENED REGIONS FROM SAID HEAT SEALED AREAS SO THAT EACHOF SAID WEAKENED REGIONS EXTENDS ACROSS SAID BODY FLANKED ON OPPOSITESIDES BY ONE OF SAID BANDS AND ONE OF SAID HEAT SEALED AREAS, WHEREBYINDIVIDUAL BAG SECTIONS HAVING SAID BANDS AT THEIR OPEN ENDS MAY BEDETACHED FROM SAID BODY BY TEARING AT SAID WEAKENED SECTIONS.